Submarine

Death haunts the depths,
A manmade shark,
A machine of war fathoms down,
In the cold below,
It is on the trail of prey,
A cyclopean eye guiding the way,
Stalking those unaware seals of steel above,
Merchant ship or frigate,
Following the reverberations of their iron lungs,
The word is given,
Doom is silently unleashed at knots,
And once the hunt is over,
And the prey is scrap metal,
Fade like orcas into the dark.